While configuring HADR with SSL between Primary DB and Standby DB, standby DB failed to be started

with the following error:

ADM12510E  Unable to establish HADR primary-standby connection with
          host: "192.168.22.20". Reason code: "13"

The error code indicates the following :

13

         The HADR_SSL_LABEL configuration parameter is not valid or has
     expired on the primary database or the standby database.

The following message can be found in db2diag.log:

<timestamp>          LEVEL: Error
PID     : 1234                TID : xxxx PROC : db2sysc 0
INSTANCE: db2inst 1             NODE : 000            DB   : SAMPLE
HOSTNAME: host1
EDUID   : 1234                   EDUNAME: db2hadrs.0.0 (SAMPLE) 0
FUNCTION: DB2 UDB, High Availability Disaster Recovery, HADR_SHARED::hshSslHandshake, probe:10245
MESSAGE : ADM12510E  Unable to establish HADR primary-standby connection with
          host: "192.168.22.20". Reason code: "13"

To resolve the problem, firstly verify HADR_SSL_label is correctly configured in your database configure parameters.

You can verify the certificate used in HADR_SSL_label has been added to your key db on Primary and Standby:

gsk8capicmd_64 -cert -list -db <full path to your key db> -stashed

Another thing to investigate is whether database configure parameter HADR_TARGET_LIST on Primary has included the standby database to be established

and vice versa.